Page 248 - Problem-Based Feline Medicine

240 PART 4 CAT WITH URINARY TRACT SIGNS

If using lente, NPH or ultralente insulin, adjust – If cat has been treated with insulin for more than
dose based on nadir (lowest) glucose concentration 2 weeks, and total dose is 1 U/cat q 12 h or less,
and clinical signs. Do not use pre-insulin blood glu- and pre-insulin glucose is ≤ 10 mmol/L (≤ 180
cose concentration to increase the dose, only to mg/dl, withhold insulin and check subsequent
decrease the dose. There is little appreciable insulin blood glucose concentrations to determine if the
action after 8–12 h, so for most cats on these insulins, cat is in diabetic remission.
the pre-insulin glucose concentration cannot be – If nadir glucose concentration < 3 mmol/L (< 54
decreased by increasing insulin dose. In general, aim mg/dl) decrease dose by 1 U/cat/injection.
for a glucose nadir of 7–9 mmol/L (126–162 mg/dl) – If clinical signs of hypoglycemia develop, then
in the first 1–2 months. Later a nadir of 5–6 mmol/L reduce dose by 50%.
(90–108 mg/dl) can be achieved in cats that are well ● Insulin dose may be maintained, increased or
controlled. decreased depending on the water intake, urine
glucose, clinical signs and length of time the cat
If using glargine or PZI, adjust the dose based on
has been treated with insulin.
nadir (lowest) glucose and pre-insulin glucose con-
– If pre-insulin glucose concentration 11–14
centration (concentration immediately before next
mmol/L (198– 252 mg/dl) or
insulin injection).
● If nadir 3–4 mmol/L (54–72 mg/dl) clinical param-
The following criteria can be used for adjusting eters are essential for adjustment of insulin dose.
insulin dose.
Most cats are well controlled on:
● Indications for increasing dose of insulin (recom-
● 0.2–0.9 U/kg q 12 h of lente insulin (median dose of
mendations assume insulin is being given twice
porcine lente was 0.5 U/kg q 12 h); only 10–15%
daily):
require 1 U/kg or more. Most cats are controlled on
– If pre-insulin glucose concentration is > 12
2–3 U/cat q 12 h.
mmol/L (216 mg/dl), then increase dose by
● 0.3–1.2 U/kg q 12 h of PZI (average dose of PZI is
0.5–1 U/cat/injection provided nadir glucose is
0.9 U/kg q 12 h); only about 10% of cats require
also high (glargine and PZI only)
more than 2 U/kg q 12 h. Most cats are controlled
AND / OR
on 4–5 U/cat q 12 h .
– If nadir glucose concentration is > 10 mmol/L
● 0.25–0.5 U/kg q 12 h of glargine (average dose is
(180 mg/dl) then increase dose by 0.5–1
< 0.5 U/kg q 12 h). Most cats are controlled on 1–2
U/cat/injection. For well controlled cats after
U/cat q 12 h, only a few cats require doses of 4–6
several weeks of therapy, an upper cut–point of
U/cat q 12 h, and the requirement for these high
> 7 mmol/L (126 mg/dl) can be used.
doses may resolve within weeks.
– If water intake is > 40 ml/kg on wet food or
● Using glargine, cats with exemplary control have
> 100 ml/kg on dry food and glargine or PZI are
nadir glucose concentrations of 4–7 mmol/L
being used, then increase dose by 0.5–1
(72–126 mg/dl) and peak glucose concentrations of
U/cat/injection. Dose may need to be increased
≥ 11 mmol/L (200 mg/dl).
or decreased if water intake is excessive when
using lente insulin. Diabetic remission usually occurs in the first 4
● Indications for maintaining the same dose: months of therapy, and occurs most often in the first
– If pre-insulin glucose concentration is ≥ 10–12 month of treatment in cats on glargine. Impending
mmol/L (≥ 240–360 mg/dl) remission is suggested by a negative urine glucose
AND/OR measurement, and a pre-insulin blood glucose concen-
– If nadir glucose concentration is 5–9 mmol/L tration of < 12 mmol/L (216 mg/dl). Decrease insulin
(90–162 mg/dl). For well controlled cats aim for dose gradually to 0.5–1 U q 12 h or even q 24 h. If
a nadir of 4–7 mmol/L (72–126 mg/dl). urine glucose is still negative and pre-insulin blood
● Indications for decreasing the dose of insulin: glucose is still low on a minimal dose of insulin, stop
– If pre-insulin glucose concentration is ≤ 10 insulin and monitor blood glucose for 12–24 h. If it
mmol/L (≤ 180 mg/dl) decrease dose 0.5 remains low, send the cat home on a low-carbohydrate
U/cat/injection. diet and re-evaluate in 1 week. The owner should